A vehicle fuel tank can include a vent valve communicating with a fuel tank. The vent valve can allow air and/or fuel vapor to escape the fuel tank as the fuel tank is being filled. The vent valve can include an elastomeric seal mounted on a flapper. The combined elastomeric seal and flapper can be referred to as a flapper assembly. The elastomeric seal can seal against a valve seat.
Generally, the flapper assembly can ride on a float that is positioned within the fuel tank or on a lever system associated with the float. It can be desirable to allow the flapper assembly to be moveable relative to the float so that misalignment of the float with the valve seat will not inhibit the flapper assembly from being flush with the valve seat during sealing. As the liquid in the fuel tank rises, the float rises and lifts the flapper assembly against the valve seat to close the vent valve. When the rate of air/vapor flow through the vent valve becomes relatively high, the flapper assembly can be drawn up, off of the float, and into engagement with the valve seat.
The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named Inventor, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.